Bowling pin with plastic protective cladding

ABSTRACT

A bowling pin having a preformed wood body or core encased in a plastic cladding, the cladding being a polyurethane and the pin having a de-adhering coating on the core, the bond strength of the coating to the core or to the polyurethane being less than the bond strength of the polyurethane to the core or the cohesion of the coating layer per se is less than the adhesion of the coating to the core or to the polyurethane.

lnfantino 1 Feb. 20, 1973 541 BOWLING PIN WITH PLASTIC 3,520,969 7/1970Smith .;273/82 R x PROTECTIVE CLADDING 3,018,106 1 1962 Satchel] et al...273/82 R 2,876,011 3/1959 Hunt ..273/82 R [751 Inventor: mam,ChaPPaqua, 3,220,731 11/1965 Gennino et al ..273 82 R 3,257,113 6/1966Medney ..273/82 R [73] Assignee: AMF Incorporated Primary ExaminerGeorgeJ. Marlo [22] plied 1970 Assistant ExaminerRichard J. Apley [21] App].N0.: 86,394 AttorneyGeorge W. Price and Thomas M. Hammond [52] US. Cl...273/82 R, 273/DIG. 3, 273/DIG. 4,

- 273/010. 8, 273/DIG. 9, 273/010. 12, [57] ABSTRACT 29 A bowling pinhaving a preformed wood body or core Cl. encased in a cladding thecladding being a [58] Field 01 Search ..273/DIG. 3, DIG. 4, DIG. 8,polyurethane and the pin having a de adhering coating 273/DIG' 82 on thecore, the bond strength of the coating to the 82 82 B core or to thepolyurethane being less than the bond strength of the polyurethane tothe core or the cohe- [56] References C'ted sion of the coating layerper se is less than the adhe- UNITED STATES PATENTS sion of the coatingto the core or to the polyurethane.

3,298,690 1/1967 Berry et al ..273/82 R (POLYURETHANE) 76 (DE-ADHERINGCOATING) w 1 Claim, 3 Drawing Figures PMENTEU 3,717, 344

(POLYURETHANE) 76 (DEADHERING /5 comma) INVENTOR. JOSEPH ROCCO INFANTINOBOWLING PIN WITH PLASTIC PROTECTIVE CLADDING This invention relates tobowling pins and a method for making the same and more particularly toan improved bowling pin having wood body or core which is clad with apolyurethane plastic and having a de-adhering coating on the core orbody, the bond strength of the coating to the core or the polyurethanebeing less than the bond strength of the polyurethane to the core or thecohesion of the coating layer per se is less than the adhesion of the.coating to the core or to the polyurethane.

Generally, it has been conventional practice in manufacturing plasticcoated bowling pins having wooden 'cores to apply to the wood core aplurality of layers of plastic coating until a sufficient depth has beenprovided. This procedure is time consuming, cumbersome, expensive andoften results in plastic coating which delaminates from the pin coreunder rigorous impact when in actual use. In addition, it has also beenconventional to apply primer coats of various types upon the wooden corebefore application of the plastic cladding to increase or enhance thebonding of the plastic cladding to the pin core. Although pinsmanufactured in accordance with the known procedures have more than metminimum commercial requirements, they still present certaindisadvantages. This is especially so in regard to polyurethane cladbowling pins wherein the plastic is applied to a wooden core. Forexample, polyurethane clad bowling pins having wooden cores tend to growpreferentially in certain regions upon continued impact due to varyingwood hardness. This growth is localized and manifests itself as bumps orblisters which not only caused decreased pin life and premature crackingof the plastic coat but also malfunctioning of automatic pinspottingdevices, such as those generally in current use.

Studies have shown that the region of the pin at the periphery of thebumps or blisters exhibits especially good adhesion. In compressionmolding the polyurethane coating on the wood cores, the pressures andheat involved cause the coating to adhere tenaciously to the wood at theball impact region. However, upon ball impact, the coating eventuallyloses adhesion nonuniformly. Generally, this is due to the variation inthe wood grain of the core. When regions of good adhesion surround aregion of poor adhesion, or wood delamination, a condition forblistering, is set up. This is so since in such a region the peripheralarea is tightly bonded to the wood, whereas the center of the region isfree to grow on impact. Consequently, repeated impact under conditionsof use cause the formation of bumps or blisters and also leads toeventual cracking at the blister edges. There exists a need, therefore,to overcome these disadvantages and the present invention provides abowling pin and a method for manufacturing the same which overcomes thementioned disadvantages and fills this need.

It is an object of the present invention to provide a plastic coatedbowling pin of increased durability.

It is a further object of the invention to provide a bowling pin havinga preformed wood core encased in polyurethane cladding and having ade-adhering coating on the core wherein the bond strength of the coatingto the core or the polyurethane is less than the bond strength of thepolyurethane to the core or the cohesion of the coating layer per se isless than the adhesion of the coating to the core or to thepolyurethane.

It is a further object of the invention to provide a method for making abowling pin having a preformed wood core encased in polyurethanecladding and having a de-adhering coating on the core wherein the bondstrength of the coating to the core or the polyurethane is less than thebond strength of the polyurethane to the core or the cohesion of thecoating layer is less than the adhesion of the coating layer to the coreor to the polyurethane.

Additional objects and advantages of the present invention will becomeapparent from the following description which is to be taken inconjunction with the accompanying drawing wherein:

FIG. 1 is a view, partially in section, of a bowling pin in accordancewith the invention and in which the wood core is coated with ade-adhering coating in the ball impact region and a plastic cladding ofpolyurethane resin and having an integrally formed base;

FIG. 2 is an elevational view showing a mold which may be employed tosupport the pin core which is coated with the de-adhering coating in theball impact region and having polyurethane plastic preforms positionedthereon and wherein the plastic flows over the core to encase thebowling pin in a polyurethane composition; and

FIG. 3 illustrates the pin configuration and approximate dimension of apartially cured polyurethane preform relative to the bowling pin corecoated in the ball impact region with a de-adhering coating as used in apreferred method of manufacturing a bowling pin in accordance with theinvention.

Referring now more particularly to FIG. 1, there is illustrated there abowling pin in accordance with the invention and generally designated bynumeral 10. Pin 10 comprises a wood body or core 12 of maple or othersuitable hard wood, which may also have a conventional dowel supportrecess 14. The core is encased in accordance with the invention with acladding or cover of polyurethane 16. Disposed between the polyurethanecladding 16 and the body or core 12 is a de-adhering coating 18 locatedpreferably around the ballto-pin contact region extending to about 2inches above and 1.5 inches below this area, although it may be appliedto the entire core surface.

Although a bowling pin in accordance with the invention may be preparedby a wide variety of processes, a preferred technique which results inexcel lent products involves the preparation of a polyurethane preform20 generally of a contour such as shown in FIG. 3, two of which aresuitably secured to the core or body 12. In the illustrated embodiment,two preforms 20 on opposite sides of the core 12 have been found to giveeminently satisfactory results. It is to be understood, however, thatany suitable number of preforms could be used, if desired, depending onsize and thickness. Preforms 20 exhibit such thickness that they adhereto the body or core 12 which has been coated with the de-adhering 18when pressed against the coated core. The coated core and preforms, asassembled, are then placed in a mold 22 and molded under heat andpressure until the preforms of polyurethane flow around the core toproduce an essentially uniform layer or cladding over the entireperipheral or surface area of the coated core.

In the preferred method for manufacturing of bowling pins in accordancewith the invention the polyurethane surface layer or cladding 16 ismolded directly on the coated core and attaches thereto with greataffinity. Except for some flash, which may occur in molding, each pinremoved from the mold usually has a smooth, glossy and attractiveappearance. Insignia and neckbands may then be applied in order tocomplete the preparation of the pin for commercial utilization.

As mentioned hereinabove and as shown in FIG. 1 of the drawing, the bodyor core 12 is provided with a recess 24 at its butt or base end. Afterthe polyurethane flows, during the molding operation, an extra thicknessor bead 26 is formed. The polyurethane adheres to the coated core andconforms exactly to the contour of the recess 24. Integral base 28 whichis formed reinforces the base of the pin, resulting in reduction of coredamage which is usually brought about due to conventional groovings inpin bases, such as required for effectively seating separate bases. Theconstruction embodying such an integral base reduces the manufacturingcosts because it eliminates several machining and assembling operations.It also increases durability of the base and, therefore, most important,the service life of the pin.

The preparation of polyurethane compositions useful to clad wood coresin accordance with the invention usually involves a two-step process inwhich the polyol is heated with an excess of an organic polyfunctional,i.e., a di-, or tri-, isocyanate and then mixed and reacted with asuitable diamine such as 4,4 'methylene bis (2 chloroaniline), availablecommercially as MOCA; or methylene dianiline, for example.

f various polyols, which may be used in the reaction with thepolyfunctional organic isocyanates, e.g., diisocyanates, so as toprepare the isocyanate-terminated polymer, the polyalkylene etherglycols are preferred. These glycols have the general formula:

HOC,.H ,,-(0--C,,H ,,),OH wherein the value of x is such as to give amolecular weight less than about 8,000 when reacted with the isocyanateto form the polyurethane prepolymer, and n is an integer having a valueof at least 2 and not greater than 8.

When C 11 is C H the polyol may be considered as a derivative ofethylene oxide or ethylene glycol. When G i-i iS the polyol can beconsidered as a derivative of propylene oxide or propylene glycol. WhenC,,l-l is C l-l the polyurethanes comprise those available commerciallyfrom E. I. -du Pont as Adiprenes. These polymers may be consideredderivatives of 1,4 butanediol, HO CH OH, or of tetrahydrofurane Wgt.percent free NCO Approx. Mol. Wgt.

In accordance with the present invention, the preferred polyalkyleneether glycol is the addition product of tetramethyleneglycol having amolecular weight of at least 500 and a free NCO percentage of at least 4percent. This is a simple product formed from a relatively few moleculesbut the polyol may be the inter-reaction product from many molecules.Where propylene oxide is used, for example, a branched chain isobtained.

The fundamental polyol unit need not be a simple glycol with adjacenthydroxyls but may be a diol where the hydroxyls are not adjacent as inthe following: HO-(CH }40H. The simplest polyether polyol from this baseis: HO "(CH ).,--0(CH 9- 0H. Also there may be other than four methylenegroups and the polyether polyol may be of a more complex typerepresented by a condensation product of two or more difierent polyols(or polyols and ethylene oxide type compounds). Examples are hexanetriol and propylene oxide or hexane triol, pentane diol and propyleneoxide. Many isomers and mixtures may be in the product. Suitablepolyols, for example, are disclosed in US. Pat. Nos. 2,901,467 and2,917,489.

The isocyanates employed in synthesizing the polyurethanes may bealiphatic or aromatic. The most common aliphatic diisocyanate isdiphenyl-methane diisocyanate, commonly known as MDI. The most commonlyused aromatic diisocyanate is tolylene diisocyanate, popularly known astoluene diisocyanate or TDl. This name is used to include the isomersand mix tures of isomers of tolylene diisocyanate. The most commonlyused of all diisocyanates is the TDI -2O mixture of 2,4-tolylenediisocyanate and 2,6-tolylene diisocyanate. Each NCO radical in thesecompounds may react in any one of various fashions. Due to the reactionspossible, the large molecules formed will have multiple cross-links; themore numerous these are, in general, the more rigid and hard the finalpolymer will be; the less numerous, the softer and more flexible thepolymer will be. The reaction to form a macromolecule provides athermosetting polymer. In general, these can be post-formed by theapplication of heat and pressure, so that these materials, in fact, arethermoplastic thermosets. During the forming operation, the partiallycured preform is further cured but not necessarily to completion.Thereafter, the product can be virtually post-cured by heating in atunnel or allowing it to stand at room temperature for several weeks.Usually normal periods of storage prior to delivery are suflicient tocomplete the cure.

Although reactions go to virtual completion, it should be noted thatthey are reversible, so that new equilibria can be established withchanges in propermontan, as well as fatty acids, such as stearic acidand the like.

Suitable de-adhering coatings of the epoxy resin type include a widevariety of materials in the class of resins referred to as epoxy resins.Any of the various compounds known as epoxy resins such as thecompositions described in U. S. Pat. No. 2,633,458, may be used in theirfully cured state. Epoxides are manufactured chiefly by the reaction ofepichlorohydrin with bisphenol A. Epoxidized novolacs (condensate ofphenol with an aldehyde) may also be used and are availablecommercially. Epoxy resins also may be manufactured by known processesemploying peracetic acid. Generally, the epoxides contemplated asde-adhering coatings are those of the general formula:

0 lem na l (11H: 0 062 ono1120 ocmoncmoQ-p-Qoomom-qun L CH; 0m

substituted on aromatic rings are preferred. From about 4.0 to 11.0molar proportions of organic diisocyanate reactant is generallyemployed. Other polyfunctional isocyanates may also be used such as thetri-isocyanates, e.g., toluene triisocyanates, alone or admixed with oneor more diisocyanates. In this regard, see for example US. Pat. No.2,531,392.

The de-adhering coating components suitable for use in the practice ofthis invention are commercially available. Generally, they comprisematerials in which the bond strength of the coating to the core or tothe polyurethane is less than the bond strength of the polyurethane tothe core or the cohesion of the coating layer per se is less than theadhesion of the coating to the core or to the polyurethane.Consequently, adhesion between the polyurethane cladding and the core isdecreased to a substantially uniform level by coating the core with suchde-adhering products. These materials include a wide variety ofproducts, some of them being film formers, such as, for example,cellulosics, thermosetting resins, polyalkylene and polyester films andtapes and the like.

Examples of cellulosics suitable for de-adhering coatings in thepractice of the invention are cellulose nitrate, cellulose acetate,cellulose acetate-butrate, ethyl cellulose, cellulose propionate andother cellulosic ethers and esters.

Examples of thermosetting resins are fully cured epoxy resins,polyurethanes and silicone resins. Exemplative of 'polyalkylene andpolyester films and tapes which may be applied as de-adhering coatingsare films and tapes of polyethylene, polypropylene and polyestersgenerally. In addition, other film formers such as polyvinyl, alcoholsand lecithins may also be utilized.

In addition to the film formers, powdered lubricious solids, applied asdusts or from liquid dispersions, may also be utilized as de-adheringpin coatings in carrying out the practice of the invention. Examples ofsuch materials are fluoroearbons, talcs, stearates, graphite andpowdered polyethylenes. Various oils and waxes are also suitable asde-adhering coatings. These include silicone oils, such as dimethylsilicone, paraffins, polyethylene glycols having molecular weights aboveabout 2,000, natural waxes, such as camauba wax and wherein n has avalue of from 0 to 7. Those in which n has a value greater than 7 haveincreasing viscosity and consequently a diminishing coefficient ofimpregnation. Expressed alternately, suitable epoxy resins are fullycured epoxy resins which have been defined as polyesters containing ahighly reactive epoxy or oxirane group at each terminal separated by analternating aromatic and aliphatic system containing hydroxyl groups,are not included by air, have long storage life and cure hard. The epoxyresins are generally hardened or solidified by a variety of curingagents such as various amides, amines, acids, or by another resin forexample. Curing agents and amount of each type used are well known, see,for example, Columns 10 and l l of U. S. Pat. No. 2,872,427. In usingthe epoxy resin as a deadhering coating, a solvent or non-solventvehicle may be used. The ratio of curing agent to epoxy preferablyvaries between 2-25 parts per hundred parts of resin although amountsgenerally in the range of 0.5 percent to 30 percent may be employed.

Illustrative examples of suitable curing agents within the abovecategories are materials such as: primary and secondary aliphaticamines, e.g., diethylenetriamine, ethylenediamine, triethylenetetramine,tetraethylenepentamine; hydroxyaliphatic amines, e.g., N-(hydroxyethyl)diethylenetriamine and N,N' -bis (hydroxyethyl) diethylenetriamine;polyalkylene polyamines; acrylonitrile-acrylamide copolymers;acrylonitrile-amine adducts, e. g., cyanoethyL diethylenetriamine;aliphatic amine adducts, e.g., an adduct of liquid epoxy resin with anexcess of polyamine such as the product Shell Development Co., availableas curing agent U; phenyl tertiary amines, e.g.,tri-(dimethylaminomethyl) phenol; acid anhydrides, e.g., dodecylsuccinicanhydride and methyl Nadic anhydride in the presence of a tertiary aminecatalyst such as benzyldimethylamine; boron trifluoride complexes. e.g.,the complex formed by neutralizing BF with an amine which provides amixture which is stable for long periods of time at room temperature andwill cure in 4-6 hours at about C. Reactive flexibilizing agents areused to eliminate brittleness in some epoxy-amine or epoxy-anhydridesystems. In referring to flexibilizing agent for the tie-adheringcoating this means that the coating after curing is in a state ofincreased toughness as distinguished from brittleness. The property offlexibilized resin is such that it has an impact resistance thatprevents the wood substrate coated therewith from shattering underconcussive forces. For this purpose, polysulfide rubbers in combinationwith an amine may be used. Various commercially available polyamideresins such as those containing amide groups in the polymer structurewith or without one or more additional modifying groups such as, amino,cyano, and hydroxy units may effectively be used to function both ascuring agent and as flexibilizing agent.

Various aliphatic epoxies such as a diepoxide in which the two aromaticmembers are bridged by a long aliphatic chain, e.g., eight to 18 carbonatoms, may also be used as flexibilizers. Aliphatic amines and alkyldiamines, e.g., t-butylamine, hexamethylene-diamine,

CH3 CH3 CH3 CHa--&liOSliO$i,l-Si(CHzOa LOH; CH3 CH3 wherein n is aninteger from 2 to about 100 and greater. In addition, hydroxysubstituted polysiloxanes having the general formula on; om om om OH;

I ,l I

()II: LA)"; (I)

wherein x is selected from the group consisting of methyl radicals andhydroxyl radicals and n is an integer from 2 to about 40 and greater arealso useful in carrying out the practice of the invention astie-adhering coatings. In regard to these hydroxy substituted materials,which are mono-, di-, and trihydroxy substituted, they are generallyemployed in the presence of an alkali metal salt of a lower organic acidsuch as acetic acid, propionic acid, butyric acid and the like. In thepresence of atmospheric moisture, the acid salts activate the silanolgroups to form a cross-linked network having linkages by the two or morepolysiloxane chains. Obviously, in such a case, the remaining bonds onthe silicone will contain organic substituant groups depending upon theparticular substitutant group on the polysiloxanes which are beingcross-linked.

Generally, in employing the polysiloxanes or any of the other materialsdisclosed as suitable as de-adhering pin coatings in carrying out thepractice of the present invention they are normally utilized bydispersing in a suitable carrier or vehicle. The vehicle is generally anorganic compound such as petroleum naphtha, trichloroethylene and othersuitable organic dispersants. The dispersion of the polysiloxanes in theorganic carrier may vary widely but as a practical manner is generallyin a range from about 1 to about 30 percent by weight, based on thetotal weight of the dispersion. Moreover, where the hydroxy substitutedpolysiloxanes are used, the alkali metal salt of the lower organic acidsmentioned above is employed in a range of from about 0.01 to about 0.20percent by weight, based on the total weight of the dispersion.

Where true films and tapes are employed as de-adhering pin coatings suchas the polymeric ethylenes, propylenes, and esters mentioned above theygenerally have an average molecular weight in a range from about 10,000to about 150,000 or more determined by ASTM method D-l601-58T. Such isalso true of the polyvinyl alcohols. The polyvinyl alcohols aregenerally employed in suitable vehicles in amounts mentioned above. Onthe other hand, the films and tapes are generally wrapped around the pincore.

In regard to the lecithin types of materials, they are generallyphosphatide compounds prepared by reacting a polyhydric alcohol by anesterification process using a fatty acid and phosphoric acid to formthe ester and then in turn combining the esterified polyhydric alcoholwith a nitrogen containing compound such as betaine or ethanolamine. Theprocedures for preparing the lecithin type compound are those generallyknown in the art and the compounds have the following general formula:

wherein R and R are selected from the groups consisting of hydrogen,methyl radical and ethyl radicals or combinations thereof. In apreferred structure em ployed in the practice of the present invention,R and R are hydrogen. In employing the lecithin type com pounds in thepractice of the present invention, they, like the materials mentionedabove, are generally utilized with a suitable carrier. Examples ofsuitable carriers are water, chloroform and benzene, although othersuitable carriers or vehicles may be employed, since the material neednot be dissolved, but only dispersed in such a vehicle. Moreover, thelecithin is generally utilized in an amount of about 0.5 to about 40percent by weight in the vehicle based on the total weight thereof.

Particularly useful fluorocarbons suitable as de-adhering coatings arethose having the following structures Fl L wherein n is an integer fromabout 30 to about 500 or greater and those having the formula Ll i ll.

wherein n is an integer from about 20 to about 400 or greater and isselected from the group consisting of hydrogen, chlorine, Generally,trifluorocarbons are used as dusts or dispersed in suitable carrierssuch as naphtha in about 3 to 30 percent by weight dispersion, based onthe total weight of the dispersion.

Stearates suitable for use in the present invention include the alkalimetal stearates potassium, sodium and calcium stearates and metallicstearates such as zinc stearate, aluminum stearate and the like. On theother hand where fatty acids are employed stearic acid is a preferredmaterial although generally fatty acids containing from about C to C areuseful as de-adhering pin coatings. These materials are used in asuitable carrier or vehicle in practicing the invention.

Generally speaking, in carrying out the practice of the invention, asmentioned hereinabove, the de-adhering pin coatings can cover completelythe entire wooden core of a bowling pin. On the other hand, it isgenerally preferred that the de-adhering pin coatings be utilized inrelatively minor amounts so that they substantially and completelypenetrate the wood core, having no measureable thickness, although as apractical matter the de-adhering pin coatings can be anywhere from about1 mil to as much as 20 mils in thickness. In addition, although thesecoatings can be employed to cover the entire pin core, they aregenerally utilized to cover only that portion of the core in thevicinity of the ball-to-pin impact region. In application of ade-adhering pin coat, therefore, the coating is generally applied to thecore in an area extending upwardly from about the ball impact region toabout 2 inches above the point of contact and about 1% inches below thepoint of contact of the ball with the pin.

As mentioned hereinabove, the materials employed as de-adhering pincoatings in the practice of this invention are generally utilized in avehicle or carrier. Any suitable vehicle or carrier can be used.However, the vehicle or carrier is generally an organic material such astoluene, xylene, benzene, aliphatic naphtha, hexane, octane and othersimilar materials. Additional carriers which can be employed arepetroleum naphtha, trichloroethylene, water and chloroform. Numerousother materials which are known to be useful as vehicles may also beused as carriers. The particular carrier for use with any one materialis readily determinable. It is preferred, however, that the carrier be arelatively volatile material so that it can be disposed of by dryingafter the de-adhering coating is applied to a pin core. Moreover, thecarrier may be a solvent or non-solvent, that is, a dispersant for theparticular deadhering coating material being utilized. Generally, thede-adhering coating material is employed in a range of about 0.5 toabout 50 percent by weight in a suitable carrier based on the totalweight of the carrier material. Preferably, however, it is employed inamounts of from about 1 to about 40 percent by weight. It is to benoted,

methyl radicals and CF;,.

moreover, that the de-adhering coating material is most preferablyemployed in relatively small amounts in the vehicle or carrier, that is,in a range of about 1 to 10' percent by weight based on the total weightof the carrier.

In connection with the polyurethane cladding, although a cladding of athickness of about 50 mils is generally preferred as a practical matter,the bowling pins of this invention can have a coating of a thickness ina range from about 20 mils to about 200 mils.

In manufacturing a bowling pin in accordance with the invention, apreferred method is to apply the de-adhering pin coatings to the woodcore and thereafter apply the polyurethane cladding to the core byutilizing appropriate molding apparatus. The de-adhering pin coating maybe applied by brushing, spraying, pouring, wiping or dipping the pincore in an appropriate dispersion of the coat material. Generally, acore so coated is then dried with heat or simply permitted to dry atroom temperatures for a period generally ranging from about 10 minutesto about 2 hours or until dry. In those cases where a curing-type ofsystem is being utilized as a deadhering pin coating, the coated coremay be held overnight to permit curing to become complete. The corehaving the de-adhering pin coating thereon is thereafter completed bycladding it with the polyu? rethane material. In application of thepolyurethane, a cladding of the plastic is first prepared as a preformwhich is applied to the core and subsequently molded in suitable moldingapparatus so that the plastic comprising the preform flows and encasesthe core.

One particularly useful apparatus for molding the preformed compositionover the pin core and which is illustrative only is shown in FIG. 2 ofthe drawing. The mold 22, as shown, comprises mold halves 32 and 3.4which may be suitably equipped with heating elements 36 and 38. As analternative, in order to provide the required heat, the molds may beplaced between heated platens. In order to keep the core centered in themold recesses 40 and 42 of the mold halves, respectively, a centeringblock 44 having a pin 46 is provided. Pin 46 extends into dowel supportrecess 14 in the pin core and is conveniently arranged to form the baseand to be accommodated by the mold, being securely held therein. As anaid in assuring more precise and prompt centering of the core in themold, a ring or band 48, provided with outwardly extending projections50 of sufficient thickness to center the heated end of the core, isaffixed to the pin core. Heated or separated patch spacers (not shown)of suitable thickness to serve the same purpose may be intermittentlyattached to the pin head before the core with the preforms as a unit isintroduced into the mold. The band (or spacers) preferably comprise acomposition which is the same or similar to the polyurethane utilizedfor the preforms from which the protective surface layer is formed.Consequently, upon molding and curing, the band blends into the plasticcladding and becomes an integral part thereof. Moreover, it is to beunderstood that it may be desirable depending on the mold and itsposition and the rigidity of the pin core holding means, to form theband (or spacers) of a composition which is wholly compatible with butmelts at a higher temperature than the polyurethane preforms or it maybe the same composition at a different curing stage.

In connection with the nature of the bond forces in utilizing ade-adhering pin coating in accordance with the invention, it is to benoted that the average bond peel strength of polyurethane to wood is ina range from about 14 to 24 lbs. of inch width of polyurethane cladding.In contrast to this, the average bond peel strength of polyurethane in abowling pin utilizing the 'de-adhering pin coatings disclosedhereinabove is in a range of from about 2 to 18 lbs. per inch width ofpolyurethane cladding. The average bond peel strength is determined bycutting an area of the plastic cladding about 1 inch wide byapproximately 4 to 6 inches long on sets of five pins and then pullingthis off perpendicu' lar to the surface by the application of increasingweights and calculating the average range.

The following illustrative examples are provided in order that theinvention may be better understood. The examples being illustrativeshould not be interpreted as indicative of limitation on compounds orconditions stated. In the examples, unless otherwise stated, all partsand percents are by weight and a polyurethane cladding of 50 milsthickness is applied to the pin core.

EXAMPLE I In a suitable apparatus equipped for mixing, two solutions,(I) and (II), to prepare the polyurethane preforms were mixed at roomtemperature and deposited in preform molds having a recess correspondingessentially to the lengthwise shadow of the pin and having a depth ofapproximately 150 mils. The mixture is used in approximatelystoichiometric proportions, i.e., about 100 parts by weight of solution(I) and about 86.5 parts by weight of solution (ll).

Solution (I) is composed of: k by weight Adiprene LD-BIS 70 Methylethylketone 30 Solution (II) is composed of:

Methylene dianiline l Mesityl oxide 85 Polyurethane of E. I. du PontNemours having 9 percent by weight free NCO and a molecular weight ofapproximately 850.

The molded preforms having the general shape shown in FIG. 3 werepartially dried to allow for some evaporation of the solvent and thenpartially cured for about 1 hour at a temperature of about 95 C. (203F.)and then removed from the mold.

Two of the preforms which are pliable and assume the contour of thebowling pin core when pressed against it, were applied to each of a setof five maple bowling pin cores which were centered in a mold as shownand described in connection with FIG. 2 and heat and pressure wereapplied, i.e., by heating in molds for 6-8 minutes at 100C. (212F.)until the preform composition flows and forms a uniform envelope on thecores. The clad cores were removed from the molds. They were thensubjected to additional treatment which converts them into completedpins. The cure was continued subsequently after the additional treatmentby passing through an oven at 65C.

-(l49F.) for 40-90 minutes or by storage for several weeks at moderatetemperatures. The bowling pins so prepared had an average bond peelstrength of 14-24 lbs. per inch width.

The above procedure was repeated on another set of five pins except thata 3 percent dispersion in naphtha of porticulate polytetrafluoroethyleneof average particle size of 1-5 microns and having an average molecularweight of 50,000 according to the manufacturers specifications wasapplied to the pin cores by dipping the cores in the dispersion to theball-to-pin impact region to provide deadhering pin coatings. Thecoatings were dried at 72 to 74F. for 1 hour to eliminate the naphtha.Thereafter, the molded preforms were positioned on the cores as statedabove and molding was carried out by subjecting the cores to 400 psigand held in the molds for 7% minutes at 230F. After marking andtopcoatin g, the pins were aged at room temperature about F. for 21 daysprior to testing. Upon testing, the pins had an average bond peelstrength of 4-8 lbs. per inch width. In addition, the degree of releaseof the polyurethane cladding after 500 lines of actual bowling was aboutpercent of the ball impact area. Moreover, the pins manifestedessentially no blistering even after 2,500 lines of bowling use. Incontrast, the pins which contained no de-adhering coatings showed onlyan 18 percent degree of release of the polyurethane coating at the ballimpact area and blistering occurred after 1,000 lines of play.

EXAMPLE II Solution I: Parts by weight Adiprene I..I)-l67 40 MOCA 34Epon 815 60 Polyurethane of E. l. duPont Nemours Co. having 6 percent byweight NCO and a molecular weight of approximately 1500.

4.4 methylene his (Z-chloraniline).

Shell Chemical Company liquid epoxy resin containing butyl glycidy etheras reactive diluent.

The polyurethane and epoxy are mixed at room temperature and the MOCA atC. (212F.) is added.

The temperature of the mix is approximately 50C.

(122F.). The preforms are molded and cured for 40-90 minutes atapproximately C. (250F.). The preform composition was applied to a setof five cores as shown in FIG. 2, which thereafter were placed in molds(at same temperature and time) and cured at a temperature ofapproximately l27C. (260F.) for approximately 4 hours. The aboveprocedure was repeated on an additional set of five cores except that a5% solution of hydro lecithin inmethylene chloride was applied bybrushing to the ball-to-pin impact region of the wood cores. Thecoatings were dried for 10 minutes after which a second coat was brushedon the cores and the coated cores were dried for an additional '30minutes at 72F. Molding was carried out as in the preceding example withsubsequent marking and topcoating and aging of the pin.

The average bond peel strength of the polyurethane to the wood cores was18-24 lbs. per inch width. In contrast, the pins having the de-adheringcoatings had a bond peel strength of 2-7 lbs. per inch width. The degreeof coating release after 500 lines of actual bowling use for the pinshaving the de-adhering pin coatings was 95 percent of the ball impactarea, in contrast to the pin having no de-adhering coatings which showeda coating release of 18 percent of the ball impact area. Moreover, thepins with the deadhering coatings manifested essentially no blisteringeven after 2,500 lines of play in contrast to the pins not having thedeadhering pin coatings which became blistered after 1 ,200 lines ofplay.

EXAMPLE III The procedure of Example I was repeated using instead thefollowing two-part composition:

TiO, pigment Solution II, molten MOCA 250F. (121C.)

Solutions I and II were mixed and poured into a mold and formed intopreforms 20 which weight 90-100 grams. The preforms were aged in themolds at room temperature for 40-60 minutes. After the preforms wereapplied, as in Example I, to a set of five bowling pin cores, the pincores with preforms 20 adhering thereto were placed in molds, preheatedfor 60-75 seconds at 230F. (1 C.) and partially cured for 6-10 minutesat 230F. (l 10C.) to a point where the molded pins could be removed fromthe molds and handled. The procedure was repeated except that a 4percent dispersion of a hydroxy substituted polysiloxane having anaverage molecular weight of about 4,000 calculated by known intrinsicviscosity methods and containing 1.5 percent of sodium acetate byweight, based on the total weight of the polysiloxane innaphthatrichloroethylene blend (50:50) was sprayed on the ball-to-pinimpact region of a set of five pin cores. The coated cores werepermitted to stand at 68through 74F. for 16 hours and subsequentlymolded as in the prior examples after which marking, topcoating andaging was carried out as in the prior examples.

The average bond peel strength of the pins having the de-adheringcoating was 2 to 4 lbs. per inch width in contrast to the pins whichcontained no de-adhering coatings which had an average bond peelstrength of 14 through 24 lbs. per inch width. Moreover, the degree ofcoating release after 500 lines of bowling use on those pins having thedeadhering pin coatings was 100 percent of the ball impact area incontrast to 18 percent of the ball impact area on those pins which hadno de-adhering coatings. In addition, the pins having the de-adheringcoatings showed no evidence of blistering after up to 2,500 lines ofuse, whereas blisters occurred in the pins which did not employ thede-adhering coatings after 1,000 to 2,000 lines of play.

EXAMPLE IV The procedure of Example I was repeated using the i4following two-part composition:

Parts by Formulation of the two-part mix is: weight Adiprene LD-315(100C.) 100 MOCA (100C.) 25-30 The mix was charged into the preformedmold cavity at approximately C. (185F.) and held for 40 to 60 minutes atroom temperature. Two of the preforms are thereafter placed on a set offive wood cores which were positioned in molds, the molds were closed ina hydraulic press providing 12-20 tons pressure for 7-10 minutes at C.(230F.). Molds with heated platens were used. Cure was then effected byheat for 40 minutes at 63C. (F.). The procedure was again repeated onanother set of five pin cores except that nitrocellulose was sprayed onthe pin cores before application of the polyurethane coating. Thenitrocellulose pins had an average bond peel strength of 9 to 11 lbs.per inch width in contrast to the polyurethane coated pins having nod-adhering coatings which had an average 14 to 24 lbs. per inch widthbond peel strength. In addition, the degree of coating release after 500lines of actual bowling use was 33 percent of the ball impact area onthe pins containing nitrocellulose in contrast to 18 percent of the ballimpact area on the pins which did not contain the coating release agent.Moreover, no evidence of blistering was noticeable after 2,500 lines ofuse on the nitrocellulose coated pins, whereas the pins containing node-adhering coating had distinct evidence of blistering around the ballimpact region after 1,000 to 2,000 lines of play.

Like results are obtained when any of the materials disclosedhereinabove are employed as de-adhering coatings.

The bowling pin of the present invention exhibits many advances as doesthe process for the manufacture thereof. For example, bowling pinsprepared in accordance with this invention have excellent longevity inactual play. They may be manufactured on known equipment and withchemical constituents readily available commercially. Moreover, abowling pin according to the invention can be manufactured without anysubstantial increase in costs. Numerous other advantages will be readilyavailable to those skilled in the art.

It will be apparent to those skilled in the art that variousmodifications may be made in the product and in carrying out the processof this invention without departing from the spirit and scope of theinvention. Ac-

cordingly, the invention is not to be limited except as

